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dnl AMD K7 mpn_popcount, mpn_hamdist -- population count and hamming
dnl distance.
dnl Copyright 2000, 2001, 2002 Free Software Foundation, Inc.
dnl
dnl This file is part of the GNU MP Library.
dnl
dnl The GNU MP Library is free software; you can redistribute it and/or
dnl modify it under the terms of the GNU Lesser General Public License as
dnl published by the Free Software Foundation; either version 3 of the
dnl License, or (at your option) any later version.
dnl
dnl The GNU MP Library is distributed in the hope that it will be useful,
dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
dnl Lesser General Public License for more details.
dnl
dnl You should have received a copy of the GNU Lesser General Public License
dnl along with the GNU MP Library. If not, see http://www.gnu.org/licenses/.
include(`../config.m4')
C popcount hamdist
C P3 generic 6.5 7
C P3 model 9 (Banias) ? ?
C P3 model 13 (Dothan) 5.75 6
C K7 5 6
C unsigned long mpn_popcount (mp_srcptr src, mp_size_t size);
C unsigned long mpn_hamdist (mp_srcptr src, mp_srcptr src2, mp_size_t size);
C
C The code here is almost certainly not optimal, but is already a 3x speedup
C over the generic C code. The main improvement would be to interleave
C processing of two qwords in the loop so as to fully exploit the available
C execution units, possibly leading to 3.25 c/l (13 cycles for 4 limbs).
C
C The loop is based on the example "Efficient 64-bit population count using
C MMX instructions" in the Athlon Optimization Guide, AMD document 22007,
C page 158 of rev E (reference in mpn/x86/k7/README).
ifdef(`OPERATION_popcount',,
`ifdef(`OPERATION_hamdist',,
`m4_error(`Need OPERATION_popcount or OPERATION_hamdist defined
')')')
define(HAM,
m4_assert_numargs(1)
`ifdef(`OPERATION_hamdist',`$1')')
define(POP,
m4_assert_numargs(1)
`ifdef(`OPERATION_popcount',`$1')')
HAM(`
defframe(PARAM_SIZE, 12)
defframe(PARAM_SRC2, 8)
defframe(PARAM_SRC, 4)
define(M4_function,mpn_hamdist)
')
POP(`
defframe(PARAM_SIZE, 8)
defframe(PARAM_SRC, 4)
define(M4_function,mpn_popcount)
')
MULFUNC_PROLOGUE(mpn_popcount mpn_hamdist)
ifdef(`PIC',,`
dnl non-PIC
RODATA
ALIGN(8)
L(rodata_AAAAAAAAAAAAAAAA):
.long 0xAAAAAAAA
.long 0xAAAAAAAA
L(rodata_3333333333333333):
.long 0x33333333
.long 0x33333333
L(rodata_0F0F0F0F0F0F0F0F):
.long 0x0F0F0F0F
.long 0x0F0F0F0F
')
TEXT
ALIGN(32)
PROLOGUE(M4_function)
deflit(`FRAME',0)
movl PARAM_SIZE, %ecx
ifdef(`PIC',`
movl $0xAAAAAAAA, %eax
movl $0x33333333, %edx
movd %eax, %mm7
movd %edx, %mm6
movl $0x0F0F0F0F, %eax
punpckldq %mm7, %mm7
punpckldq %mm6, %mm6
movd %eax, %mm5
movd %edx, %mm4
punpckldq %mm5, %mm5
',`
movq L(rodata_AAAAAAAAAAAAAAAA), %mm7
movq L(rodata_3333333333333333), %mm6
movq L(rodata_0F0F0F0F0F0F0F0F), %mm5
')
pxor %mm4, %mm4
define(REG_AAAAAAAAAAAAAAAA,%mm7)
define(REG_3333333333333333,%mm6)
define(REG_0F0F0F0F0F0F0F0F,%mm5)
define(REG_0000000000000000,%mm4)
movl PARAM_SRC, %eax
HAM(` movl PARAM_SRC2, %edx')
pxor %mm2, %mm2 C total
shrl %ecx
jnc L(top)
movd (%eax,%ecx,8), %mm1
HAM(` movd (%edx,%ecx,8), %mm0
pxor %mm0, %mm1
')
orl %ecx, %ecx
jmp L(loaded)
ALIGN(16)
L(top):
C eax src
C ebx
C ecx counter, qwords, decrementing
C edx [hamdist] src2
C
C mm0 (scratch)
C mm1 (scratch)
C mm2 total (low dword)
C mm3
C mm4 \
C mm5 | special constants
C mm6 |
C mm7 /
movq -8(%eax,%ecx,8), %mm1
HAM(` pxor -8(%edx,%ecx,8), %mm1')
decl %ecx
L(loaded):
movq %mm1, %mm0
pand REG_AAAAAAAAAAAAAAAA, %mm1
psrlq $1, %mm1
psubd %mm1, %mm0 C bit pairs
movq %mm0, %mm1
psrlq $2, %mm0
pand REG_3333333333333333, %mm0
pand REG_3333333333333333, %mm1
paddd %mm1, %mm0 C nibbles
movq %mm0, %mm1
psrlq $4, %mm0
pand REG_0F0F0F0F0F0F0F0F, %mm0
pand REG_0F0F0F0F0F0F0F0F, %mm1
paddd %mm1, %mm0 C bytes
psadbw( %mm4, %mm0)
paddd %mm0, %mm2 C add to total
jnz L(top)
movd %mm2, %eax
emms
ret
EPILOGUE()
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